1. Technical Field
This invention relates to a technique of detecting a failure of a microphone of a hearing aid.
2. Description of Related Art
A hearing aid including two microphones for providing directivity for the user includes a correction circuit described below configured to eliminate an amplitude difference between output signals of the microphones so as to correct difference in sensitivity caused by the individual difference between the microphones (for example, see JP-A-2003-506937).
The correction circuit includes: a first microphone; a first ND converter connected on an output side of the first microphone; a second microphone; a second A/D converter connected on an output side of the second microphone; a microphone sensitivity correction unit connected on an output side of the second A/D converter; a hearing assistance processing unit to which an output of the microphone sensitivity correction unit and an output of the first A/D converter are input; a microphone sensitivity correction value calculation unit to which the output of the first A/D converter and an output of the second A/D converter are input, and one output of which is connected to the microphone sensitivity correction unit; a D/A converter connected on an output side of the hearing assistance processing unit; and a receiver connected to an output side of the D/A converter.